Npp steroid wikipedia

Damage incurred by traumatic brain injury is believed to be caused in part by mass depolarization leading to excitotoxicity . One way in which progesterone helps to alleviate some of this excitotoxicity is by blocking the voltage-dependent calcium channels that trigger neurotransmitter release. [64] It does so by manipulating the signaling pathways of transcription factors involved in this release. Another method for reducing the excitotoxicity is by up-regulating the GABA A , a widespread inhibitory neurotransmitter receptor. [65]

As indicated above, ACTH is a cleavage product of the pro-hormone, proopiomelanocortin (POMC), which also produces other hormones including α-MSH that stimulates the production of melanin . A family of related receptors mediates the actions of these hormones, the MCR, or melanocortin receptor family. These are mainly not associated with the pituitary - adrenal axis. MC2R is the ACTH receptor . While it has a crucial function in regulating the adrenal, it is also expressed elsewhere in the body, specifically in the osteoblast , which is responsible for making new bone, a continual and highly regulated process in the bodies of air-breathing vertebrates. [10] The functional expression of MC2R on the osteoblast was discovered by Isales et alia in 2005. [11] Since that time, it has been demonstrated that the response of bone forming cells to ACTH includes production of VEGF , as it does in the adrenal. This response might be important in maintaining osteoblast survival under some conditions. [12] If this is physiologically important, it probably functions in conditions with short-period or intermittent ACTH signaling, since with continual exposure of osteoblasts to ACTH, the effect was lost in a few hours.